The present application finds particular application in hybrid commercial vehicle brake systems, particularly involving a cruise control activated brake regeneration system. However, it will be appreciated that the described technique may also find application in other brake regeneration systems, other vehicle energy management systems, or other brake control systems.
Classical approaches to brake regeneration include regenerative braking that warns a driver when regenerative braking is necessary. In this manner, conventional systems can discourage aggressive braking and encourage smoother even braking.
One approach relates a hybrid vehicle with a regenerative braking system that cooperates with the antilock braking system with adaptive cruise control. If cruise control is active, the regenerative braking is applied during a downhill grade to improve battery recharge while slowing the vehicle. Another approach relates to a method that uses regenerative braking to maintain a desired vehicle speed. Yet another approach relates to a hybrid system that evaluates vehicle route information to predict when braking may occur. In this manner, the system is able to keep the battery in an optimized charge state. Another technique relates to a regenerative braking system that reduces vehicle speed during downhill travel, and reduces speed during uphill travel by applying increased brake torque.
One problem with heavy duty hybrid vehicles occurs when aggressive drivers wait too long before applying the brakes when approaching an object. It is well known in the heavy duty hybrid vehicle field that energy efficiency related to brake regeneration is driver-dependent. Hybrid truck and bus manufactures often provide training and a dash-mounted fuel efficiency display to provide driver education and feedback to avoid “heavy foot” brake applications and sudden stop scenarios, in the hope that the aggressive drivers will learn from the training, heed the training gauge, and moderate their brake applications. However, aggressive drivers often decelerate only at the very last moment, using a full apply brake application to quickly stop rather than a more gentle application and a more gradual stop. Such last moment brake application does not allow time for the brake energy to be regenerated by the traction motor and stored as potential in high voltage DC batteries. Therefore, in conventional approaches energy is wasted, more fuel is consumed, and more emissions are generated, which is problematic considering a main purpose of hybrid vehicles is to conserve fuel and reduce emissions. Currently, there is no energy management system that can facilitate brake regeneration by automatically mitigating the heavy foot scenario. Aggressive braking (e.g., hard stops) wastes energy and increases brake wear, heat and brake fade. Moreover, aggressive braking necessitates a heavy brake application and is very dangerous for both the driver and surrounding traffic.
The present innovation provides new and improved systems and methods that facilitate energy recovery by mitigating heavy brake applications associated with fast object approach and aggressive driving techniques, which overcome the above-referenced problems and others.